INDEX. 



233 



Michell conceives nil nebulae to be stellar 

 clusters, 20. 



Milky Way, Huygens on the, 38. 



Mimas, a satellite of Saturn, 174. 



Moon, myths respecting the, 113, 115 ; 

 estimate of the heat of its surface, 130 ; 

 numerical data, 141; moonlight, 142; 

 capable of producing heat, 143 ; styled 

 by the Indians, King of the stars of 

 cold, 143 ; eclipses, 145 ; predictions 

 from the color of the eclipsed body, 

 147 ; lunar twilight disproved, 147 ; 

 probably a voiceless wilderness, 148 ; 

 irradiation, 148; spots, 149; supposed 

 to reflect the surface of our planet, 150; 

 topographical chart, 151 ; 6o-called seas, 

 151 ; mountains, 153 ; comparison of 

 height with the mountains of the 

 Earth, 153; ray -systems, 154; annular 

 plains, 154 ; craters of elevation, 155 ; 

 rills, 157 ; influence on the Earth, 157. 



Mountains of the Moon, 153. 



Mundus Jovialis, a work by Galileo, 16. 



Nebula, the first isolated, discovered, 16. 



Nebulas, Lacaille's classification of, 19 ; 

 discoveries of the Herschels, 21 ; of the 

 Earl of Rosse and others, 22 ; probably 

 no essential physical distinction be- 

 tween, and clusters of stars. 23 ; ques- 

 tion of the existence or non-existence 

 of a self-luminous, vaporous matter, 24 ; 

 elliptical, 31 ; annular, 32 ; planetary, 

 33 ; nebulous stars, 34 ; galaxy of, not 

 confirmed by recent observation, 36. 



Nebular theory, the, 20 ; independent of 

 the theory of sidereal aggregation, 21. 



Nebulous masses, regular, 29 ; irregular, 

 33 ; these latter mostly situate near the 

 Milky Way, 34 ; extraordinary size of 

 some, and singular forms of others, 36. 



Nebu'ous spots, 13 ; number whose posi- 

 tions have been determined, 14 ; early 

 notices of, 14 ; Galileo's discoveries, 17 ; 

 Huygens, 19; Lacaille, 19; other in- 

 vestigators, 20; the discoveries of the 

 Herschels. 21 ; the Earl of Rosse, 22 ; 

 Sir John Herschel's distribution of, 27. 



Nebulous stars, mentioned by Hippar- 

 chus, Geminus, and Ptolemy, 15 ; a 

 modern division of regular nebulae, 34. 



Neptune, considerations on the distance 

 of, 178 ; numerical data, 178 ; claims to 

 the discovery of, 178. 



Neptune, satellites of, 180. 



Northern Catalogue of the Herschels, 25. 



Northern hemisphere possesses many 

 nebulae, and but few clusters of stars, 

 27. 



November period, meteors of the, 209, 

 215. 



Nubecula Major and Minor, 20, 46. 



Number and epoch of discovery of the 

 principal planets, 89. 



Nutation of the Earth's axis, 105, 125. 



October, falling stars in, 214. 



Olbers's conjecture as to the asteroids 

 being fragments of a single destroyed 

 planet, 164 ; on shooting stars, 216. 



Orbits, inclination of, planetary, 121 ; 

 cometary, 198. 



Orion, nebula in the sword of, 18, 36 ; in 

 the head of, 36 ; trapezium not sur- 

 rounded by a nebula, 39 ; new stars 

 discovered in the trapezium, 39, 



Pallas, discovery of, 100 ; elements, 161. 



Parthenope, discovery of, 101 ; elements, 

 163. 



Penumbras of the solar body, 67. 



Periodic meteors, number of, observed 

 at different hours, and in different 

 months, 213. 



Perpetual spring, its undesirable nature, 

 123. 



Perseus, falling stars issuing from, 210. 



Peruvian seven-day week, an error, 98. 



Peter Martyr, his description of the Ma- 

 gellanic Clouds, 46 ; on a fall of aero- 

 lites, 219. 



Photosphere of the nebulous stars, 34 ; 

 of the Sun, 62. 



Picard investigates the nebula in Orion, 

 19. 



Pisces, nebulous region of, 28. 



Planetary discovery, epochs of, 58. 



Planetary motion, three great laws of, 228. 



Planetary nebulae, 33; mainly found in 

 the southern hemisphere, 33. 



Planetary system, stability of, how de- 

 monstrated, 229. 



Planets and their satellites, general con- 

 siderations, 88 ; principal planets, 89 ; 

 discovery, 89 ; names, 91 ; planetary 

 signs, not of ancient date, 94 ; days and 

 metals named from, 94 ; early conjec- 

 tures that other planets remained to 

 be discovered, 99 ; periods of discovery 

 since the invention of the telescope, 

 100 ; classification hi two groups, 102 ; 

 exterior, generally larger than the in 

 tenor, 103 ; absolute and apparent mag 

 nitudes, 104 ; arrangement and dis- 

 tances. 107 ; assumed laws, by Titius 

 and Bode, and Wurm, 116; masses, 

 118 ; densities, 119 ; periods of revolu 

 tion, and axial rotation, 120; inclina- 

 tion, 121 ; eccentricity, 127 ; intensity 

 of the Sun's light, 130. 



Planets, secondary, numerical data, 131. 



Planets, the small, numerical data, 160 ; 

 table of elements, 163 ; Olbers's con- 

 jecture as to their origin, 164. 



Plateau on irradiation, 148. 



Principal planets, 89. 



Proselenes, astronomical myth of the, 

 113. 



Ptolemy mentions nebulous stars, 15. 



Regular nebulas, classification of, 29. 

 Revolution, periods of, of the planets, 



120 ; of comets, 195. 

 Rhea, a satellite of Saturn, 174. 

 Robinson, Dr., nebulae resolved by, 22. 

 Rosse, Earl of, discoveries by means of 



his powerful telescope, 22 ; his caution, 



23. 

 Sabbath, used as a name for the whol« 



week, 95. 



